A pulse oximeter is a non-invasive, medical device that measures oxygen saturation, or how much oxygen is in the bloodstream. Pulse oximeters for home use generally attach to a finger with a clip-on probe and display the oxygen reading and heart rate on a small LED screen. Using a pulse oximeter is easy, but first, let’s get more familiar with how it works.

How a Pulse Oximeter Works

Whenever you take a breath, oxygen enters the breathing passages and flows into the lungs. Once in the lungs, it passes through tiny capillaries where it enters the bloodstream and attaches to hemoglobin, a protein inside red blood cells. Hemoglobin molecules transport oxygen to the cells, tissues and organs of the body. A hemoglobin molecule is fully saturated with oxygen when it’s loaded with 4 oxygen molecules.

A pulse oximeter probe contains a light source, a light detector and a microprocessor. The color of blood varies depending upon how much oxygen it contains. Pulse oximeters consist of two light emitting diodes: a red light that you can see as it shines through the tissues and an infra-red light that you can’t see. It also contains two light collecting sensors that measure the amount of red and infra-red light emerging from the tissues passed through by the light rays. The absorption of light is processed by the device and an oxygen saturation level is reported as a percentage onto an LED screen. This number represents the percentage of hemoglobin molecules in your blood that are saturated with oxygen. Normal oxygen saturation ranges between 95-100 percent. A pulse oximeter also measures and displays your heart rate.

Using a Pulse Oximeter

A pulse oximeter is the perfect companion for your Inogen At Home. Better yet, it’s an essential travel accessory that can be easily tucked into your Inogen One G3 travel case. To use a pulse oximeter, take the following steps:

  1. Making sure your hands are warm, clip the probe onto a finger.
  2. Keep your hands still and wait for a reading. This usually only takes a few seconds.
  3. Record the reading in a notebook or on a separate piece of paper to refer to it later if necessary. This way, your doctor can monitor your readings, as well.

Tips for Getting a Good Reading

Getting a good reading depends upon adequate blood flow to the tissues. Pulse oximeters are generally accurate, however there are several factors that can interfere with an accurate reading. Check out the following tips to get the best oximetry reading possible:

  • Cold hands and fingers equate to an inaccurate oximetry reading. Warm your hands by rubbing them together, placing them in a warm towel or soaking them in a sink of warm water. Be sure to dry them completely before using your pulse oximeter.
  • Avoid wearing dark nail polish as this can interfere with the pulse oximeter’s signal resulting in an inaccurate reading. Be aware that acrylic nails may also cause a poor reading. Try a French manicure instead.
  • If you can’t get a good reading on your fingers, try your toes or earlobes. Again cold extremities may alter the reading so make sure your feet are nice and warm.
  • Body movement can affect the accuracy of an oximetry reading. Patients with conditions that result in hand mannerisms or tremors should have pulse oximeters attached to the toes or earlobes to greatly reduce the effects of movement that can influence readings.
  • If you initially get a low reading, wait a few minutes with the probe attached to your finger to see if it increases. If it doesn’t, warm your hands and retake. If it still isn’t reading correctly, try the toes or earlobes. Ask your health care provider at which point they should be notified of a low reading.
  • Medical devices are delicate instruments. Avoid submerging any medical equipment, including your pulse oximeter, in water.
  • Be sure to replace the battery of your pulse oximeter regularly, according to the manufacturer’s instructions.

If you’re on supplemental oxygen, ask your doctor if you should be titrating your oxygen dose to your pulse oximetry reading. If the answer is yes, be sure a health care professional shows you how to do this correctly. Never titrate your oxygen unless your health care provider tells you to do so.

For more information about using a pulse oximeter, read Inogen’s Home Oximetry Tips.